Tissue engineering is a very complicated and highly technical field. One of the possible methods for tissue engineering involves the growth of new tissue using a framework or scaffold from tissues harvested from an animal or human. In such methods, the harvested tissue is first treated to remove all cell debris and other material. This process prepares the tissue for reseeding with fresh cells to promote new cell growth and proliferation. However, the process of removing all cell debris has the effect of placing stress on the harvested tissue, usually resulting in the loss of collagen alignment and collagen structure. The potential for varying degrees of collagen fraying and alterations of collagen fiber tertiary structure and polarity of the collagen triple helix exists after this decellularization process. Collagen that has not been irreversibly cross-linked is degraded by MMPs and re-enters the protein synthesis pathway via its constituent amino acids. The loss of collagen structure leads to voids in the structure of the tissue wall and destabilization of the harvested tissue. Additionally, typical enzyme, detergent and solvent treatments used for decellularization result in significant loss of extracellular matrix (ECM) proteins and ECM soluble molecules such as proteoglycans and glycosaminoglycan's (GAGs). There is significant moisture loss and the protective envelope of proteoglycans and GAG's that surround the structural proteins are significantly depleted.
Promoting and accelerating cell growth once the tissue is reseeded is also a difficult process. In order to promote growth of synthetic tissue and cell growth, the harvested tissue, acting as the frame or scaffold, requires a very specific environment. This process can be further complicated by any allergies or rejection responses a patient might experience when the engineered tissue is introduced into the recipient.
Accordingly, what is needed are preparations which rebuild the tertiary structure of collagen to provide a strong framework or scaffolding to support the growth of new cells. What is further needed is an environment that restores or prevents further loss of moisture, ECM proteins, ECM soluble molecules, lubricant characteristics, and emollient characteristics of an engineered or decellularized tissue. What is still further needed is an environment that promotes and supports the growth of cells seeded into decellularized harvested tissue to create engineered tissues.